Final answer:
The force that causes the molten pool to seek a lower level when welding in any position is gravity.
Step-by-step explanation:
When welding in any position, the force that causes the molten pool to seek a lower level is gravity. Gravity pulls objects towards the center of the Earth, so when the molten pool is formed during welding, it naturally flows downwards due to the force of gravity. This is why it's important for welders to properly position the joint and use supports if needed to prevent the molten pool from flowing in an undesired direction.